[meteorite-list] Pluto's Fate to be Decided by 'Scientific andSimple' Planet Definition

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Tue Aug 15 09:02:24 2006
Message-ID: <20060815130211.11134.qmail_at_web36906.mail.mud.yahoo.com>

Hi all -

Ed Weiler once asked me if I expected him to find
everything in the Oort Cloud. At the timer, I told
him no, that would not be necessary, I just expected
him to find what was in-bound as early as possible.

Now I've changed my mind, and I have a question for
you. What kind of platform would you send out there
to map the Kuiper Belt and/or Oort Cloud - optics,
power, launcher, propulsion, trajectory? How many of
them?

all the best,
Ed

--- "Sterling K. Webb" <sterling_k_webb_at_sbcglobal.net>
wrote:

> Hi, All,
>
> Pluto has infrastructure going for it: 75 years
> of textbooks and references to it as planet, down
> the
> mnemonic they use in grade school:
> My Very Educated Mother Just Served Us Nine
> Pizzas... for Mercury, Mars, Venus, Earth...
>
> I think the idea of the "Dwarf Planet" moniker
> is a mistake.
> The three classes of planet proposed. Terrestrial,
> Gas Giant,
> and Dwarf seems sensible at first, but it has flaws.
> Small
> Rocky Worlds is a valid class. Gaseous Giants is OK
> (but
> Neptune may be a small super-terrestrial with a
> whopping
> big atmosphere, but why quibble...?).
>
> What happens to the category of "dwarf planet"
> when
> and if we discover a TNO bigger than Mercury at 100
> AU?
> Or a TNO bigger than Mars at 150 AU? Why would I
> think that would happen?
>
> Well, I've been reading everything I could get
> my hands on
> about the planets for fifty years. When I started,
> the books
> said that Pluto was probably 10,000 to 15,000 miles
> across,
> then all of sudden, the newer ones reported sadly
> that Pluto
> was only 6500 miles across, then 3700 miles, then
> 2500, then
> maybe less than 1500, and hey! it wasn't really a
> planet, just an
> escaped moon of Neptune, and that was the end of the
> solar
> system, nobody home all the way out to Oortville.
> Then, Pluto got itself a moon, a big one, and it
> was a planet
> again. But that was it -- nothing else. Then, OK,
> there are a
> few things out there beyond Pluto, but nothing big
> and not
> very many of those.
> Then, OK some of those things are as big as the
> bigger
> asteroids, but they're just freaks. Heck, some of
> them may have
> wandered in and been captured by our solar system.
> Basically,
> the outer system is empty...
> Then, OK, there's thousands of things out there,
> but they're all
> small, insignificant iceballs, like 25-50 km; don't
> worry. Well,
> OK, one of these new asteroidal things out there
> past Pluto seems
> to be bigger than Pluto and, oh, there's a few more
> of those
> bigger things, too. And, my God! they've got moons;
> maybe
> they're planets. And then, Pluto's got THREE moons,
> and one
> of the newbies has got two...
> And just this month, an occultation experiment
> demonstrated
> that the K-Belt has got lots of medium 100-200 km
> objects, quite
> a few in fact... Well, how many? Er, about a
> quadrillion. (Yeah,
> that's what they said, a quadrillion.) I'm not even
> sure how many
> is a quadrillion, 10^15? It's a lot, I know that.
>
> Do you see a trend here, in fifty years of data?
>
> This is clearly detection-driven discovery. With
> every
> improvement in our ability to detect, we find more,
> for 30
> years now. Before you assume that you would always
> find
> more, not so. One of the reasons for improving
> detection
> is to reach completeness: you improve and you don't
> find
> anything new; you finally got it all. But so far,
> the Outer
> System just gets busier and busier.
>
> One of the clues is that 2003UB313 and 2005EL61
> and
> so forth are not that much further away than Pluto,
> within
> 10-12 AU. The detections are using parallax
> displacement --
> watch it for three weeks and see if it moves
> relative to the
> background sky. But objects further away move more
> slowly;
> you have to watch them longer to detect their
> movement.
> At this point, the searches can't afford to spend
> that much
> time on every patch of sky, so they haven't found
> any bigger,
> further objects... yet.
>
> It can't go on forever, true. No Black Dwarf
> star at 500 AU.
> But I give it a 50-50 chance that before 2020 we
> will discover a
> TBO bigger than Mercury or even Mars. (I hope
> sooner; I
> hate waiting.)
>
> What do you do when you discover a Dwarf Planet
> BIGGER than a Regular Planet? You can only spend
> just
> so much time in committee rooms... By choosing
> "dwarf"
> as a designation you assume facts not (yet) in
> evidence.
>
> Why not just Terrestrial, Gas Giant, and
> Plutonian Planets?
> The 11 year old that suggested the name "Pluto" for
> the new
> 1930 Planet did so because he was the Greek god of
> the nether
> regions, so "Plutonian" can be taken to mean "Outer
> System"
> planets (assuming it's big enough to be round and
> orbits the
> Sun).
>
> Even if Ceres gets an upgrade, it would still
> work, as
> Ceres seems like to be "Plutonian" in composition...
> I have
> a soft spot for Ceres.
>
>
> Sterling K. Webb
>
-----------------------------------------------------------------
> ----- Original Message -----
> From: "Ron Baalke" <baalke_at_zagami.jpl.nasa.gov>
> To: "Meteorite Mailing List"
> <meteorite-list_at_meteoritecentral.com>
> Sent: Monday, August 14, 2006 6:57 PM
> Subject: [meteorite-list] Pluto's Fate to be Decided
> by 'Scientific
> andSimple' Planet Definition
>
>
> >
> >
>
http://space.com/scienceastronomy/060814_pluto_fate.html
> >
> > Pluto's Fate to be Decided by 'Scientific and
> Simple' Planet Definition
> > By Robert Roy Britt
> > space.com
> > 14 August 2006
> >
> > A new "scientific and simple" proposal to define
> the word "planet" will
> > be released Wednesday and astronomers will vote on
> it next week. It is
> > not clear whether the definition will settle a
> long-running debate on
> > the status of Pluto, however. The International
> Astronomical Union (IAU)
> > will propose wording to delineate planets from
> other small objects at its
> > 12-day General Assembly meeting in Prague. The
> meeting opened today and
> > the proposal will be released to IAU member and to
> the public Wednesday.
> >
> > Committee members will not say how Pluto will be
> defined, but the
> > diminutive planet will definitely be included in
> the wording.
> >
> > "Yes, it is very clear within what will be
> released - [Pluto] is very
> > specifically in or out," said Richard Binzel, an
> MIT planetary scientist
> > on a seven-person committee that developed the
> definition.
> >
> > "I think we have come up with a very reasonable
> definition that in the
> > end will be widely adopted," Binzel said by
> telephone from Prague today.
> > "And we will move forward. I think all will agree
> that it's time to move
> > forward."
> >
> > The big mistake
> >
> > The roots of the problem go back to 1930, when
> Clyde Tombaugh discovered
> > Pluto . It was classified as the 9th planet. But
> in recent years,
> > astronomers have found other round worlds out
> beyond Neptune that are
> > nearly as big as Pluto. One object, 2003 UB313, is
> the same size as
> > Pluto.
> >
> > All these relatively small objects have offbeat
> orbits that trace oblong
> > paths. Some, like Pluto, soar well above and below
> the main plane of the
> > solar system in which the other eight planets
> orbit.
> >
> > For these reasons, many astronomers have long said
> that it was a mistake
> > to call Pluto a planet, and many favor demoting it
> to some new class of
> > object called minor planet or dwarf planet. Some
> think Pluto should
> > remain a regular planet for cultural and historic
> reasons. But doing
> > that would logically mean defining the handful of
> other small round
> > worlds as planets. And experts say dozens if not
> hundreds more
> > Pluto-like objects remain to be found on the
> outskirts of our solar
> > system.
> >
> > For a year, a committee of planetary scientists
> within the IAU tried to
> > come up with a definition. They failed. So the IAU
> gave the task to the
> > separate 7-member panel that includes Binzel and
> author Dava Sobel.
> >
> > Owen Gingerich, an historian and astronomer
> emeritus at Harvard, told
> > NPR last week that the proposal, "will make the
> Plutocrats and the
> > children of the United States happy."
> >
> > Gingerich's words imply that Pluto will not lose
> planet status. One
> > possibility is that the proposal would have Pluto
> termed a dwarf planet
> > or minor planet. The setup would logically divide
> planets into
> > terrestrial planets (Mercury, Venus, Earth, Mars),
> giant planets
> > (Jupiter, Saturn, Uranus, Neptune) and the dwarfs.
> >
> > One possible alternative is Pluto could simply
> remain a planet with no
> > prefix. This much is known:
> >
> > "We have come up with a surprisingly scientific
> definition," Binzel
> > said. "It's both scientific and simple."
> >
> > That suggests things like size, orbital
> characteristics, location and
> > formation method might be included in the
> definition.
> >
> > One week to ponder
> >
> > A vote on the definition by IAU members is slated
> for Thursday, Aug. 24.
> > SPACE.com first reported the likelihood of this
> vote back in June (IAU
> > members must first vote on a proposal to
> re-institute their right to
> > vote on the matter).
> >
> > Most astronomers, including those very close to
> the issue, are in the
> > dark about what will happen.
> >
> > "Assuming they come up with a resolution and it is
> presented, it is
> > unclear to me if the vote will succeed," said Alan
> Boss, a
> > planet-formation theorist at the Carnegie
> Institution of Washington.
> > "Even if it does succeed I suspect some people
> will resist it."
> >
> > Boss was on the original IAU committee that tried
> to forge a definition.
> > Given the inability of that group to reach
> consensus, and the strongly
> > held opinions of various group members, Boss said
> trying to solve the
> > problem with experts outside the planetary science
> community is a
> > worthwhile experiment. But he's not sure it'll
> work.
> >
> > "I'd be thrilled and pleased, but I don't expect
> that this little
> > subgroup will come up with a definition that
> everyone can approve and
> > accept," Boss told SPACE.com today. What will
> really count, he said, is
> > what the editors of scientific journals allow to
> be printed over the
> > next 10 to 20 years.
> >
> > Everyone's favorite planet
> >
> > The controversy, which heated up in 1999 and has
> not abated since, is
> > not limited to planetary scientists.
> >
> > "Every astronomer, not just planetary scientists,
> probably has a pretty
> > strong opinion about how [Pluto] should be named,"
> Boss said. "Even
> > people on the street, elementary school teachers -
> everyone seems to have
> > an opinion on this. I think it's going to be hard
> for people to accept
> > any major changes one way or another."
> >
> > Boss said he wouldn't be surprised if the IAU vote
> will be split in
> > thirds, much like the opinions of the original
> committee charged with
> > developing a definition. And he said the vote
> should not necessarily be
> > the end of the debate. Future discoveries of
> objects beyond Neptune
> > could force continual re-evaluation of
> classification systems and
> > nomenclature.
> >
> > "It's not necessarily something that should be
> decided by a vote for all
> > time," he said. "Science keeps moving."
> >
> > Binzel is confident that resolution looms: "If we
> have done our job,
> > this will be the end of any significant debate."
> >
> > ______________________________________________
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> >
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>
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Received on Tue 15 Aug 2006 09:02:11 AM PDT